Remove all uses of 'using std::error_code' from headers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210866 91177308-0d34-0410-b5e6-96231b3b80d8

lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp

@@ -23,6 +23,7 @@
 
 using namespace llvm;
 using namespace llvm::object;
+using std::error_code;
 
 #define DEBUG_TYPE "dyld"
 

lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp

@@ -27,6 +27,7 @@
 
 using namespace llvm;
 using namespace llvm::object;
+using std::error_code;
 
 #define DEBUG_TYPE "dyld"
 

lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h

@@ -20,11 +20,9 @@
 using namespace llvm;
 
 namespace llvm {
-using std::error_code;
-
 namespace {
 // Helper for extensive error checking in debug builds.
-error_code Check(error_code Err) {
+std::error_code Check(std::error_code Err) {
   if (Err) {
     report_fatal_error(Err.message());
   }